Robert Boschgmbh

Airflow Research and Manufacturing Corporation

Bosch Automotive Systems Corporation

Bosch Automotive Motor Systems, Inc.

Robert J Van Houten

Yoonshik Shin

Mark D Caplan

Robert I Hickey

William M Stevens

Martin G Yapp

Mark L Bilodeau

David Daiute

Jeff D Booth

Steven W Day

A free-tipped axial fan assembly features a shroud barrel comprising an inlet, the radius of said inlet at its upstream end being greater than the radius of said inlet at its downstream end. An angle, in a plane including the fan axis, between the surface of said inlet and the direction of the fan axis varies non-monotonically with respect to a surface coordinate which increases with distance along the surface of the inlet.

Free-tipped axial fan assembly

An axial fan comprising a hub and a plurality of blades extending from a periphery of the hub. Each of the blades has a thickness which varies from a leading edge to a trailing edge and from a root to a tip. The blades are unevenly spaced around the periphery of the hub in a pattern which is not balanced. The fan is balanced by variance in blade thickness among the plurality of blades.

Axial fan with unbalanced blade spacing

An airflow assembly includes a fan, a shroud, a plurality of ribs, and a fan support. The fan has a number of fan blades. The shroud includes (i) a plenum defining a plenum opening located adjacent to the number of fan blades, and (ii) a barrel extending from the plenum so as to surround the plenum opening. The plenum further defines at least one airflow opening spaced apart from the plenum opening. Each of the plurality of ribs extends inwardly from the barrel. The fan support is attached to the plurality of ribs and is configured to support the fan. The at least one airflow opening is not an attachment structure or a guiding structure, is not configured to receive a fastening member, and does not function as a water drain.

Airflow assembly having improved acoustical performance

A free-tipped axial fan assembly includes a fan having a blade tip geometry which minimizes the adverse effect of a tip gap. The maximum blade thickness exhibits a significant increase adjacent the blade tip. In some constructions, the maximum thickness at the blade tip is at least 100 percent greater than the maximum thickness 0.10 R away from the blade tip. In some constructions, the trailing-edge thickness at the blade tip is approximately the same as the trailing-edge thickness 0.10 R away from the blade tip. In some constructions, the increase in blade thickness follows the square of the distance from the position where the increase begins.

Free-tipped axial fan assembly with a thicker blade tip

An airflow assembly, includes a plenum, a barrel, a fan support, a fan assembly, and a plurality of ribs. The plenum includes an opening structure defining a plenum opening. The barrel extends in a downstream direction from the opening structure, and defines a barrel space and a downstream edge. The fan support is at least partially positioned within the barrel space. The fan assembly is supported by the fan support and includes (i) a motor and (ii) a blade assembly configured to rotate about an axis. Each of the ribs extends between (i) the opening structure or the barrel and (ii) the fan support. The downstream direction is parallel to the axis. An upstream direction is opposite of the downstream direction and parallel to the axis. A plane intersects the axis and is perpendicular to the axis.

A free-tipped axial fan assembly includes fan having a blade tip geometry which provides a desired blade loading in the presence of a tip gap. The maximum camber exhibits a sudden and significant increase as the blade tip radius R is closely approached in the direction of increasing radial position. In some constructions, the maximum camber at the blade tip radius R is at least 10 percent greater than the maximum camber at a radial position r where r/R=0.95. In some constructions, the blade angle increases by more than 0.01 radians from a radial position r where r/R=0.95 to the blade tip radius R. The maximum camber at the blade tip radius R is at least 0.06 times the chord length in some constructions.

A free-tipped axial fan assembly has a skew distribution which reduces fan noise while minimizing radial tip deflection. The difference between the maximum value of leading-edge skew and the value of leading-edge skew at the fan radius is at least 10 degrees. The ratio of the difference of the leading-edge skew between the maximum value and the value at the fan radius to the difference of the trailing-edge skew between the maximum value and the value at the fan radius is at least 2.5.

Skewed axial fan assembly

High efficiency and low noise is achieved in an automotive engine-cooling fan assembly by flaring the inlet to the shroud barrel, and shaping the tips of the fan blades to conform to the shape of the inlet. Separation of the flow entering the fan is reduced by extending the flare over the axial extent of the blade tip, and tip clearance losses are reduced by controlling recirculation along the entire blade tip. Blade rake is used to minimize fan deflection, thereby allowing the use of small tip clearances, which further enhance performance.

Automotive fan assembly with flared shroud and fan with conforming blade tips

A fan and electric motor combination (or a fan adapted to be used in such a combination) which provides improved cooling for the motor, using a centrifugal impeller including rotating impeller blades. The impeller blades span between an impeller inlet and an impeller outlet, and they rotate to assist cooling airflow for the motor. Cooling airflow is also assisted by the position of the impeller in that the impeller outlet is positioned upstream of an intersection of the fan blade trailing edge and the hub. Therefore, cooling airflow is assisted by at least some (preferably all) of the pressure drop across the axial fan. If the impeller outlet is positioned still further upstream, e.g., upstream of an intersection of the fan blade leading edge and the hub, then the motor cooling airflow is assisted by all or nearly all of the pressure drop across the axial fan.

Axial fan with self-cooled motor

A cooling system for an automotive vehicle of the type having a radiator through which a coolant fluid flows includes a fan motor for driving a fan which moves air through the radiator; an alternator for supplying an output voltage to the fan motor; and a voltage regulator which selectively excites the alternator's field winding in response to a control signal, determined on the basis of at least one operational parameter of the vehicle indicative of the cooling requirements of the engine which powers the vehicle to control the output voltage of the alternator, thereby controlling the speed of the fan motor.

Dedicated alternator cooling system for automotive vehicles

A counter-rotating fan which comprises a forward-skewed upstream rotor and a backskewed downstream rotor. The counter-rotating fan may be used in a cooling module with a heat exchanger, for example as an engine cooling fan in a vehicle.

Oppositely skewed counter-rotating fans

An improvement to forwardly skewed axial fans whereby blade camber and rake are coordinated with skew. The blades are characterized in that a line defined by the points of maximum chordwise camber (f.sub.max) as a function of changing radial position (r) is on the leading edge side of the mid-chord line (M.sub.CL) at values of r toward the root of the blade, and is less forwardly skewed than the leading edge (LE), the mid-chord line (M.sub.CL), and the trailing edge (TE) of said blade; the blade is raked forwardly so that the trailing edge of the blade tip is axially forward of the trailing edge at the blade root; rake (k) increases monotonically as radial position r increases from 0.75R to 1.0R, R being the fan radius; the blade has a relatively large pitch ratio (P/D); and rake is corrected to reflect the chordwise position of maximum camber. As a result, the fan produces a flow that is generally in radial equilibrium having a reduced component of flow normal to the2 desired axial flow and normal to the tangential flow. The coordinated fan can be (but need not be) combined with a housing/band configuration for controlling airflow that recirculates (i.e., counter to the desired axial airflow) in a channel formed between the band and housing.

Forward skew fan with rake and chordwise camber corrections

An axial flow fan comprising: a cental hub rotatable on an axis; and a plurality of blades extending from the hub, each of the blades comprising a root portion adjacent to the hub, and terminating in a tip portion, the root portions of the blades being approximately evenly spaced around the hub; wherein each of the blades exhibits a curvature from the root portion of the blade to the blade's tip portion, the curvature being in a plane that is perpendicular to the axis on which the fan rotates; and wherein the curvature differs between at least two of the blades, such that the distance between the tip portions of at least wo sets of adjacent blades is unequal. The invention therefore achieves the advantage of having uneven blade spacing near the tips while maintaining high solidity near the hub, where the blade spacing is even. Uneven blade spacing near the tips reduces noise. Having high solidity near the hub, where non-dimensional loading is highest, maintains higher dynamic performance.

Variable skew fan

The invention features an axial fan for passing air through a heat exchanger, the fan comprising a hub rotatable on an axis and a plurality of blades, each of which extend radially outward from a root portion attached to the hub to a tip portion, the blades characterized by a trailing edge angle that varies by approximately 40.degree. or more over the radial extent of each blade. The blade trailing edge angle is preferably greater than 60.degree. at the root region.

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Winchester, MA, United States of America

Robert J Van Houten